The present invention relates to a new and improved roller apron framework for support- or drive rolls of a continuous casting installation or plant, wherein at least at one strand guide pat there are mounted in a common pivotable yoke two respective rollers following one another in the direction of strand travel, and such yoke can be moved by means of piston-cylinder units along guides substantially transversely with respect to the guided strand surface.
In the continuous casting art there are frequently used rollers which can be hydraulically adjusted or applied to the strand for the purpose of supporting and guiding the strand and for driving and linearly straightening curved or arcuate strands, especially steel strands possessing a liquid core. These rollers can be applied individually or in the form of assembled together groups of rollers.
It is already known in this particular field of technology to connect to a common yoke two rollers which are successively arranged in the direction of strand travel and to pivotably connect this yoke with an adjustment drive arranged between both rollers and acting transversely with respect to the guided strand surface. If unequal force components act upon such rollers arranged in a yoke, and which force components are directed tranversely with respect to the guided strand surface, then by means of the pivot axis or shaft of the yoke these force components are uniformly divided at both rollers. However, in addition to the force components acting transversely with respect to the guided strand surface there are further applied to the rollers force components which are also directed parallel to the guided strand surface due to the presence of bending- and drive forces and irregularities present at the casting or strand. These last-mentioned force components produce a tilting moment at the yoke, and thus disturb the uniform force distribution of the adjustment or contact force at both rollers arranged in the yoke. On the one hand, owing to uncontrolled and non-uniform adjustment forces and on the other hand, due to possible pivotal movement of the one roller past a pre-determined guide path line or boundary towards the strand, there can be caused strand flaws or defects and/or undesired roller flattening or the like. Moreover, there is not always insured for protection against over-loading of the rollers connected with the yoke, notwithstanding the pivotability of the yoke. Additionally, with such roller apron frameworks it is not possible to control the guide paths for the strand of the roller apron, for instance with the aid of calipers or gauges or by means of a measurement carriage or the like which can be introduced into the roller apron.